Development and validation of a simple and practical model for early detection of diabetic macular edema in patients with type 2 diabetes mellitus using easily accessible systemic variables.

OBJECTIVE: Diabetic macular edema (DME) is the leading cause of visual impairment in patients with diabetes mellitus (DM). The goal of early detection has not yet achieved due to a lack of fast and convenient methods. Therefore, we aim to develop and validate a prediction model to identify DME in patients with type 2 diabetes mellitus (T2DM) using easily accessible systemic variables, which can be applied to an ophthalmologist-independent scenario. METHODS: In this four-center, observational study, a total of 1994 T2DM patients who underwent routine diabetic retinopathy screening were enrolled, and their information on ophthalmic and systemic conditions was collected. Forward stepwise multivariable logistic regression was performed to identify risk factors of DME. Machine learning and MLR (multivariable logistic regression) were both used to establish prediction models. The prediction models were trained with 1300 patients and prospectively validated with 104 patients from Guangdong Provincial People's Hospital (GDPH). A total of 175 patients from Zhujiang Hospital (ZJH), 115 patients from the First Affiliated Hospital of Kunming Medical University (FAHKMU), and 100 patients from People's Hospital of JiangMen (PHJM) were used as external validation sets. Area under the receiver operating characteristic curve (AUC), accuracy (ACC), sensitivity, and specificity were used to evaluate the performance in DME prediction. RESULTS: The risk of DME was significantly associated with duration of DM, diastolic blood pressure, hematocrit, glycosylated hemoglobin, and urine albumin-to-creatinine ratio stage. The MLR model using these five risk factors was selected as the final prediction model due to its better performance than the machine learning models using all variables. The AUC, ACC, sensitivity, and specificity were 0.80, 0.69, 0.80, and 0.67 in the internal validation, and 0.82, 0.54, 1.00, and 0.48 in prospective validation, respectively. In external validation, the AUC, ACC, sensitivity and specificity were 0.84, 0.68, 0.90 and 0.60 in ZJH, 0.89, 0.77, 1.00 and 0.72 in FAHKMU, and 0.80, 0.67, 0.75, and 0.65 in PHJM, respectively. CONCLUSION: The MLR model is a simple, rapid, and reliable tool for early detection of DME in individuals with T2DM without the needs of specialized ophthalmologic examinations.

Association of serum lipid profile and other systemic risk factors with retinal hard exudates in diabetic retinopathy.

PURPOSE: Diabetic macular edema is one of the leading causes of vision loss across the world. Hard exudates at the macula can lead to structural abnormalities in the retina leading to irreversible vision loss. Systemic dyslipidemia and other modifiable risk factors when identified and treated early may help prevent substantial vision loss. The purpose of this study was to study the association between serum lipid levels and other systemic risk factors like hemoglobin, HbA1c, and serum creatinine with hard exudates and macular edema in patients with diabetic retinopathy. METHODS: It is a prospective cross-sectional study conducted in a tertiary health care center in South India. 96 patients having diabetic retinopathy with hard exudates were included. Modified Airlie house classification was used to grade the hard exudates. Blood investigations including serum lipid profile, hemoglobin, HbA1c, and serum creatinine were carried out. Central subfield macular thickness was measured using optical coherence tomography. RESULTS: 96 patients of type II DM with diabetic retinopathy were divided into three groups of hard exudates. A statistically significant correlation was observed between the severity of hard exudates and total cholesterol (p = 0.00), triglycerides (p = 0.00), LDL (p = 0.00), and VLDL (p = 0.00). HbA1c levels showed a statistically significant correlation with the severity of hard exudates (p = 0.09), no significant correlation was noted between hard exudates and hemoglobin levels (p = 0.27) and with serum creatinine (p = 0.612). A statistically significant association between CSMT and hard exudates (p = 0.00) was noted. CONCLUSION: In our study, we concluded that the severity of hard exudates is significantly associated with increasing levels of serum total cholesterol, triglycerides, LDL, VLDL, and HbA1c levels in type II DM patients presenting with diabetic retinopathy. The increasing duration of diabetes is significantly associated with increasing severity of hard exudates. Central subfield macular thickness increases with increasing severity of hard exudates in diabetic retinopathy.

Pre-therapeutic Biomarkers for Ranibizumab Therapy among Type 2 Diabetic Patients with Diabetic Macular Edema.

SIGNIFICANCE: A differential outcome in randomized controlled trials of anti-vascular endothelial growth factor (anti-VEGF) therapy, including ranibizumab, for diabetic macular edema is a major dilemma for planning, optimizing, and managing clinical usage. The variable outcome of the therapeutics necessitates the importance of finding a predictive biomarker for anti-VEGF therapy to improve subject selection. PURPOSE: Our study correlates the baseline pro- and anti-VEGF isoforms and its three receptors (VEGFReceptor1, VEGFReceptor2, and VEGFReceptor3) for circulatory candidate protein molecules among diabetic patients with macular edema, with the clinical outcome of ranibizumab therapy. METHODS: This study included 86 individuals who were anti-VEGF naive at the time of ascertainment but have completed the standardized therapy regimen of the clinic. Plasma proteins for pro- and anti-VEGF isoforms and its three receptors were determined in replicate by an enzyme-linked immunosorbent assay. RESULTS: The study demonstrated that 56 (65.12%) individuals benefited from the therapy in terms of letter gain (Snellen chart). Baseline plasma soluble VEGF receptor 2 (sVEGFR-2) was significantly higher among responders (65.10 pg/mL; 95% confidence interval, 55.41 to 74.80 pg/mL) compared with nonresponders (46.38 pg/mL; 95% confidence interval, 38.69 to 54.07 pg/mL; PFDR = .03). Diffuse diabetic macular edema with proliferative diabetic retinopathy increases the risk of nonresponse to the therapy by 3.03-fold (PFDR = .04). CONCLUSIONS: The present study postulates that diffuse diabetic macular edema with proliferative diabetic retinopathy and baseline circulatory soluble VEGF receptor 2 may be potential candidates as therapy-stratifying markers for ranibizumab treatment among patients with diabetic macular edema.

The association between intravitreal ranibizumab therapy and serum cytokine concentrations in patients with diabetic macular edema.

Aim: To investigate the association between intravitreal ranibizumab therapy and serum cytokine concentrations in patients with diabetic macular edema (DME). Methods: Twenty-five patients with center-involved DME were recruited prospectively. Serum samples were collected from the patients before and 4 weeks after two ranibizumab injections. The levels of 32 cytokines at these two time points were assessed using a multiplex array assay. Results: Following two ranibizumab injections, there was a statistically significant decrease in the median [interquartile range] levels of Interleukin 1-1beta (IL-1ß) from 5.56 [3.6, 8.75] to 2.33 [1.51, 2.89], Interleukin 13 (IL-13) from 4.30 [1.84, 18.55] to 0.38 [0.38, 0.78], granulocyte-colony stimulating factor (G-CSF) from 64.65 [42.9, 108] to 37.8 [27.3, 46.37], Interferon gamma (IFN-γ) from 241 [103.33, 753.4] to 94.4626 [42.04, 118.58], Interferon gamma-induced protein 10 (IP-10) from 234.68 [144.16, 285.98] to 158.73 [94.71, 198.64], Macrophage Inflammatory Protein-1 alpha (MIP-1α) from 3.65 [2.62, 11.02] to 1.41 [0.94, 1.88], and Tumor necrosis factor- alpha (TNF-α) from 131.09 [100.68,28 240.27] to 45.19 [24.04, 68.55]. There was a statistically significant increase in the levels of Interleukin 9 (IL-9) from 0.76 [0.76, 7.03] to 19.67 [5.36 27.76], Macrophage Inflammatory Protein-1 beta (MIP-1ß) from 0.28 [0.28, 30 0.28] to 6.79 [I3.74, 14.16], Vascular endothelial growth factor (VEGF) from 2.55 [2.55, 2.55] to 25.24 [14.51, 41.73], and soluble vascular endothelial growth factor -1 (sVEGFR-1) from 333.92 [204.99, 440.43] to 500.12 [38.7, 786.91]. A Bonferroni-corrected p value of 0.00156 was considered statistically significant. Conclusions: In patients with DME, intravitreal ranibizumab therapy appears to influence the serum levels of a range of cytokines. After two injections, intravitreal ranibizumab therapy appears to be associated with a significant decrease in inflammatory mediators and a rise in VEGF and sVEGFR1.

Evaluation of long-term intravitreal anti-vascular endothelial growth factor injections on renal function in patients with and without diabetic kidney disease.

BACKGROUND: Administering anti-vascular endothelial growth factor (anti-VEGF) by intraocular injection has been shown to have a safe systemic profile. Nevertheless, incidents of acute kidney injury following anti-VEGF injection have been reported. We assessed the long-term effect of multiple intravitreal anti-VEGF injections on measures of renal function in patients with diabetes including rate of change of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (ACR). METHODS: A retrospective review of patients receiving diabetic macular oedema (DMO) treatment was undertaken. Serum creatinine, ACR, number of intravitreal anti-VEGF injections and clinical characteristics were collected from electronic healthcare records (EHR). A co-efficient of eGFR and ACR change with time was calculated over a mean duration of 2.6 years. Regression modelling was used to assess variation in the number of anti-VEGF injections and change in eGFR and ACR. RESULTS: The EHR of 85 patients with DMO (59% male, 78% type 2 diabetes mellitus [T2DM]) were reviewed. On average, 26.8 intravitreal anti-VEGF injections were given per patient over a mean duration of 31 months. No association between increasing number of anti-VEGF injections and rate of eGFR decline (beta = 0.04, 95% confidence intervals [CI]: - 0.02, 0.09; p = 0.22) or ACR change over time (beta = 0.02, CI: - 0.19, 0.23; p = 0.86) was detected, following adjustment for hypertension, cerebrovascular disease, T2DM, and medications taken. CONCLUSION: Our data suggests regular long-term intravitreal VEGF inhibition does not significantly alter the rate of change in eGFR and/or ACR with increasing number of treatment injections.

A Novel Biomarker in Diabetic Macular Edema with Serous Retinal Detachment: Serum Chitinase-3-Like Protein 1.

PURPOSE: To determine whether serum chitinase-3-like protein 1 (CHI3L1) and interleukin-6 (IL-6) levels correlate with serous retinal detachment (SRD) in diabetic macular edema (DME) using spectral-domain optical coherence tomography (SD-OCT). METHODS: In this cross-sectional case-control study, 394 patients (treatment-naive DME patients, n = 218; diabetic patients without DME, n = 96; nondiabetic controls, n = 80) were included in the study. Eyes were classified according to SD-OCT features of DME: SRD, cystoid macular edema (CMO), and diffuse retinal thickness (DRT). Serum concentrations of CHI3L1 and IL-6 were analyzed using enzyme-linked immunosorbent assay. RESULTS: Serum CHI3L1 and IL-6 levels were significantly higher in DME with SRD compared to patients with CMO and DRT (p < 0.001 for all groups). Multivariate regression analysis showed that CHI3L1 and IL-6 had a stronger influence on the presence of SRD in DME (r = 1.162, p = 0.026, and r = 1.242, p = 0.016, respectively). Serum concentration of CHI3L1 was significantly correlated with that of IL-6 (r = 0.386, p = 0.0015). CONCLUSIONS: Our data suggest that serum concentrations of CHI3L1 and IL-6 are involved in the process of SRD in DME. CHI3L1 can be investigated further as a new diagnostic biomarker for DME with SRD.

Ethnic Differences in the Prevalence and Risk Factors of Diabetic Retinopathy: The Singapore Epidemiology of Eye Diseases Study.

PURPOSE: To evaluate the prevalence and risk factors for diabetic retinopathy (DR) in the Singapore Epidemiology of Eye Diseases (SEED) Study. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: Persons of Malay, Indian, and Chinese ethnicity aged 40+ years, living in Singapore. METHODS: Diabetes was defined as nonfasting plasma glucose ≥200 mg/dl (11.1 mmol/l), glycated hemoglobin A1c (HbA1c) >6.5%, self-reported physician-diagnosed diabetes, or the use of glucose-lowering medication. Retinal photographs, were graded for the presence and severity of DR using the modified Airlie House classification system. MAIN OUTCOME MEASURES: Diabetic retinopathy, diabetic macular edema (DME), vision-threatening diabetic retinopathy (VTDR), defined as the presence of severe nonproliferative or proliferative DR, or clinically significant macular edema (CSME). RESULTS: Of the 10 033 subjects, 2877 (28.7%) had diabetes and gradable photographs for analysis. The overall age-standardized prevalence (95% confidence interval [CI]) was 28.2% (25.9-30.6) for any DR, 7.6% (6.5-9.0) for DME, and 7.7% (6.6-9.0) for VTDR. Indians had a higher prevalence of any DR (30.7% vs. 26.2% in Chinese and 25.5% in Malays, P = 0.012); a similar trend was noted for any DME (P = 0.001) and CSME (P = 0.032). Independent risk factors for any DR were Indian ethnicity (odds ratio [OR], 1.41; 95% CI, 1.09-1.83, vs. Chinese), diabetes duration (OR, 1.10; 95% CI, 1.08-1.11, per year), HbA1c (OR, 1.25; 95% CI, 1.18-1.32, per %), serum glucose (OR, 1.03; 95% CI, 1.00-1.06, per mmol/l), and systolic blood pressure (OR, 1.14; 95% CI, 1.09-1.19, per 10 mmHg). Diastolic blood pressure (OR, 0.74; 95% CI, 0.65-0.84, per 10 mmHg increase), total cholesterol (OR, 0.87; 95% CI, 0.80-0.95, per mmol/l increase), and low-density lipoprotein (LDL) cholesterol (OR, 0.83; 95% CI, 0.74-0.92, per mmol/l increase) were associated with lower odds of any DR. Risk factors were largely similar across the 3 ethnic groups. CONCLUSIONS: Indian Singaporeans have a higher prevalence of DR and DME compared with Chinese and Malays. Major risk factors for DR in this study were similar across the 3 ethnic groups. Addressing these risk factors may reduce the impact of DR in Asia, regardless of ethnicity.

Plasma Vascular Endothelial Growth Factor Concentrations after Intravitreous Anti-Vascular Endothelial Growth Factor Therapy for Diabetic Macular Edema.

PURPOSE: To assess systemic vascular endothelial growth factor (VEGF)-A levels after treatment with intravitreous aflibercept, bevacizumab, or ranibizumab. DESIGN: Comparative-effectiveness trial with participants randomly assigned to 2 mg aflibercept, 1.25 mg bevacizumab, or 0.3 mg ranibizumab after a re-treatment algorithm. PARTICIPANTS: Participants with available plasma samples (N = 436). METHODS: Plasma samples were collected before injections at baseline and 4-week, 52-week, and 104-week visits. In a preplanned secondary analysis, systemic-free VEGF levels from an enzyme-linked immunosorbent assay were compared across anti-VEGF agents and correlated with systemic side effects. MAIN OUTCOME MEASURES: Changes in the natural log (ln) of plasma VEGF levels. RESULTS: Baseline free VEGF levels were similar across all 3 groups. At 4 weeks, mean ln(VEGF) changes were -0.30±0.61 pg/ml, -0.31±0.54 pg/ml, and -0.02±0.44 pg/ml for the aflibercept, bevacizumab, and ranibizumab groups, respectively. The adjusted differences between treatment groups (adjusted confidence interval [CI]; P value) were -0.01 (-0.12 to +0.10; P = 0.89), -0.31 (-0.44 to -0.18; P < 0.001), and -0.30 (-0.43 to -0.18; P < 0.001) for aflibercept-bevacizumab, aflibercept-ranibizumab, and bevacizumab-ranibizumab, respectively. At 52 weeks, a difference in mean VEGF changes between bevacizumab and ranibizumab persisted (-0.23 [-0.38 to -0.09]; P < 0.001); the difference between aflibercept and ranibizumab was -0.12 (P = 0.07) and between aflibercept and bevacizumab was +0.11 (P = 0.07). Treatment group differences at 2 years were similar to 1 year. No apparent treatment differences were detected at 52 or 104 weeks in the cohort of participants not receiving injections within 1 or 2 months before plasma collection. Participants with (N = 9) and without (N = 251) a heart attack or stroke had VEGF levels that appeared similar. CONCLUSIONS: These data suggest that decreases in plasma free-VEGF levels are greater after treatment with aflibercept or bevacizumab compared with ranibizumab at 4 weeks. At 52 and 104 weeks, a greater decrease was observed in bevacizumab versus ranibizumab. Results from 2 subgroups of participants who did not receive injections within at least 1 month and 2 months before collection suggest similar changes in VEGF levels after stopping injections. It is unknown whether VEGF levels return to normal as the drug is cleared from the system or whether the presence of the drug affects the assay's ability to accurately measure free VEGF. No significant associations between VEGF concentration and systemic factors were noted.

CHANGES IN PLASMA VASCULAR ENDOTHELIAL GROWTH FACTOR LEVEL AFTER INTRAVITREAL INJECTION OF BEVACIZUMAB, AFLIBERCEPT, OR RANIBIZUMAB FOR DIABETIC MACULAR EDEMA.

PURPOSE: The aim of this study was to investigate the changes in plasma vascular endothelial growth factor (VEGF) level depending on the severity of diabetic retinopathy (DR) or diabetic macular edema (DME) and after intravitreal injection of bevacizumab, aflibercept, or ranibizumab for treatment of DME. METHODS: Plasma VEGF level was evaluated in 72 patients with DR and changes were measured in 42 patients with DME receiving intravitreal injections of bevacizumab, aflibercept, or ranibizumab at the initial injection. RESULTS: There were no correlations between plasma VEGF level and the severity of DME or DR. Baseline plasma VEGF level (51.9 pg/mL) was significantly reduced using bevacizumab to 11.9 pg/mL after 1 week and 24.1 pg/mL after 4 weeks (P = 0.0130 and 0.0201, respectively). In aflibercept-treated eyes, plasma VEGF decreased from 52.2 pg/mL to 7.8 pg/mL and 12.6 pg/mL, respectively, at the same time points (both P < 0.001). No such reductions were observed in patients receiving ranibizumab. CONCLUSION: Baseline plasma VEGF level showed no correlations with DR or DME severity, whereas intravitreal injection of bevacizumab or aflibercept significantly reduced plasma VEGF for up to 4 weeks and ranibizumab produced no such effects. Changes in plasma VEGF level seemed not to be critical in progression or treatment of DME and DR.

Cathepsin D: an Mϕ-derived factor mediating increased endothelial cell permeability with implications for alteration of the blood-retinal barrier in diabetic retinopathy.

Inflammation plays an important role in the pathogenesis of diabetic retinopathy (DR). We have previously reported increased monocyte (Mono) trafficking into the retinas of diabetic animals. In this study, we have examined the effect of activated Monos on retinal endothelial cells (ECs). The U937 Mϕ-conditioned medium (CM) significantly decreased the transendothelial resistance of EC monolayers as measured by electric cell-substrate impedance sensing (P= 0.007). The CM was fractioned, and the effective fraction (30-100 kDa) was analyzed by liquid chromatography-mass spectrometry, and cathepsin D (CD) was identified as a major secreted product. Immunoprecipitated CD resulted in decreased resistance in ECs (P= 0.006). The specificity of CD in mediating alterations of the EC barrier was confirmed using small interfering RNA. The decreased resistance correlated with a significantly increased gap between ECs. CD altered the Ras homolog gene family, member A/Rho-associated kinase pathway with increased stress actin filament formation in the EC layer. Increased CD levels were found in the retinas of diabetic mice (3-fold) and serum samples of patients with diabetic macular edema (1.6-fold) measured by Western blot and ELISA. These findings suggest an important role for Mϕ-derived CD in altering the blood-retinal barrier and reveal a potential therapeutic target in the treatment of DR.-Monickaraj, F., McGuire, P. G., Nitta, C. F., Ghosh, K., Das, A. Cathepsin D: an Mϕ-derived factor mediating increased endothelial cell permeability with implications for alteration of the blood-retinal barrier in diabetic retinopathy.

Association of serum lipid levels with retinal hard exudate area in African Americans with type 2 diabetes.

PURPOSE: Previous studies have yielded conflicting results regarding whether serum lipid levels are associated with retinal hard exudates in diabetic retinopathy. The majority of studies have assessed hard exudates only as a dichotomous trait (presence vs. absence) and included limited numbers of African Americans (AA). The purpose of this study was to determine if there are any associations between serum lipid levels and hard exudates in AA with type 2 diabetes (T2D). METHODS: 890 AA participants with T2D were enrolled from 5 sites. Macular fundus photographs were graded by masked ophthalmologist investigators. Hard exudate areas were measured using a semi-automated algorithm and ImageJ software. Multivariate regression models were used to determine the association between serum lipid levels and (1) presence of hard exudate and (2) area of hard exudate. RESULTS: Presence of hard exudates was associated with higher total cholesterol [(odds ratio (OR) = 1.08, 95 % confidence interval (CI) 1.03-1.13, P = 0.001)] and higher low-density lipoprotein (LDL) cholesterol (OR = 1.08, 95 % CI 1.03-1.14, P = 0.005) in models controlling for other risk factors. Hard exudate area was also associated with both higher total and LDL cholesterol levels (P = 0.04 and 0.01, respectively) in multivariate models controlling for other risk factors. CONCLUSIONS: Higher total and LDL cholesterol were associated with the presence of hard exudates and a greater hard exudate area in AA with T2D. This information can be used to counsel diabetic patients regarding the importance of lipid control to decrease the risk of macular hard exudates.

SYSTEMIC PHARMACOKINETICS AND PHARMACODYNAMICS OF INTRAVITREAL AFLIBERCEPT, BEVACIZUMAB, AND RANIBIZUMAB.

PURPOSE: To evaluate the systemic pharmacokinetics (PKs) of aflibercept, bevacizumab, and ranibizumab in patients with neovascular age-related macular degeneration (AMD), diabetic macular edema (DME), or retinal vein occlusion (RVO). METHODS: Prospective, open-label, nonrandomized clinical trial of patients with AMD, DME, or RVO who were antivascular endothelial growth factor (VEGF) naïve or had not received anti-VEGF for ≥4 months. Patients received 3 monthly intravitreal injections of aflibercept 2.0 mg, bevacizumab 1.25 mg, or ranibizumab (0.5 mg for AMD/RVO, 0.3 mg for DME). The main outcome measures were serum PKs and plasma free-VEGF concentrations after the first and third injections. RESULTS: A total of 151 patients were included. In AMD/DME/RVO, systemic exposure to each drug was highest with bevacizumab, then aflibercept, and lowest with ranibizumab. Ranibizumab cleared from the bloodstream more quickly than bevacizumab or aflibercept. Aflibercept treatment resulted in the greatest reductions in plasma free-VEGF relative to baseline levels, whereas ranibizumab treatment resulted in the smallest decreases in plasma free-VEGF. CONCLUSION: The three anti-VEGF treatments examined in this analysis demonstrated notable differences in systemic PKs. Generally, the reduction in plasma free-VEGF levels correlated with elevated levels of circulating anti-VEGF agents, with the reduction in free-VEGF levels greatest with aflibercept and least with ranibizumab.

Influence of serum lipids on the incidence and progression of diabetic retinopathy and macular oedema: Sankara Nethralaya Diabetic Retinopathy Epidemiology And Molecular genetics Study-II.

IMPORTANCE: The importance of lipids on incidence and progression of diabetic retinopathy has not been studied in the Indian population. BACKGROUND: To elucidate the influence of serum lipid control on the incidence and progression of diabetic retinopathy and diabetic macular oedema in subjects with type 2 diabetes. DESIGN: Population-based longitudinal observational study in a hospital setting. PARTICIPANTS: Eight hundred ninety subjects were examined at baseline and follow-up. METHODS: Diabetic retinopathy was graded per Modified Early Treatment Diabetic Retinopathy Study scales; 45°, 4-field dilated stereoscopic digital photography was performed with an additional 30°, 7-field for those who had retinopathy. Macular oedema was evaluated per Proposed International Clinical Diabetic Retinopathy and Diabetic Macular Oedema Disease Severity Scales. MAIN OUTCOME MEASURES: Association of serum lipids and incidence and progression of diabetic retinopathy. RESULTS: Poor control of total cholesterol was associated with the incidence of sight-threatening retinopathy (odds ratio = 7.2 [95% confidence interval: 1.5-34.3], P = 0.012) and macular oedema (odds ratio = 5.5 [95% confidence interval: 1.4-27.4], P = 0.037) after adjusting for potential confounders. Poor control of triglycerides was associated with progression to proliferative diabetic retinopathy (odds ratio = 3.2 [95% confidence interval: 1.1-10.5], P = 0.048). Risk for incident macular oedema (P = 0.041) and progression to proliferative diabetic retinopathy (P = 0.028) was greater when all lipid types were abnormal. CONCLUSIONS AND RELEVANCE: Poor control of lipids is a risk factor for incidence of and progression to late stages of retinopathy. Abnormal levels of all lipid types are associated with risk of incident macular oedema and progression to proliferative diabetic retinopathy.

The Impact of Systemic Factors on Clinical Response to Ranibizumab for Diabetic Macular Edema.

PURPOSE: To evaluate the effect of systemic factors on best-corrected visual acuity (BCVA) achieved with ranibizumab (Lucentis; Genentech, Inc, South San Francisco, CA) for treatment of diabetic macular edema (DME) in the RIDE and RISE phase 3 studies. DESIGN: Exploratory, post hoc analysis of 2 randomized, double-masked, sham-injection controlled studies. PARTICIPANTS: Adults with DME, BCVA of 20/40 to 20/320 Snellen equivalent, and central foveal thickness of 275 µm or more. METHODS: Analysis of RIDE (clinicaltrials.gov identifier, NCT00473382) and RISE (clinicaltrials.gov identifier, NCT00473330) pooled ranibizumab data through month 24. Change in BCVA was assessed for association with the following covariates: age, body mass index (BMI), blood pressure, serum glucose, glycosylated hemoglobin (HbA1c), blood urea nitrogen, serum creatinine, estimated glomerular filtration rate, and blood chemistry variables. Change in BCVA at month 24 was assessed according to the following categories of diabetes medication use history: insulin only (n = 193), insulin plus other medications (n = 221), or other noninsulin medications (n = 331). MAIN OUTCOME MEASURES: Change in BCVA from baseline assessed by randomized treatment group in pooled 0.3- and 0.5-mg monthly ranibizumab groups. RESULTS: In patients with DME, vision improvement with ranibizumab was not influenced by systemic factors such as diabetes medication history, serum glucose, HbA1c, renal function, BMI, and blood pressure. Patients taking insulin with or without other medications at baseline had longer diabetes disease duration (mean, 17.4 and 20.9 years, respectively) compared with those taking other noninsulin medications (mean, 11.9 years). At month 24, among ranibizumab-treated patients, the mean BCVA change from baseline (Early Treatment Diabetic Retinopathy Study letters ± standard deviation) was not different between patients taking only insulin (12.6±11.2 letters), insulin plus other medications (12.2±12.4 letters), or other noninsulin medications (14.0±13.7 letters). Mean BCVA change also was comparable among patients taking thiazolidinediones (12.9±9.7 letters) and those not taking thiazolidinediones (13.2±13.3 letters). CONCLUSIONS: There were no associations between systemic factors (baseline values or change from baseline) and mean change of BCVA at month 24. These results suggest that visual response to ranibizumab therapy in DME was not influenced by nonocular factors related to systemic management of diabetes in the RIDE and RISE studies.

OPTICAL COHERENCE TOMOGRAPHY CHARACTERISTICS OF MACULAR EDEMA AND HARD EXUDATES AND THEIR ASSOCIATION WITH LIPID SERUM LEVELS IN TYPE 2 DIABETES.

PURPOSE: To determine whether hyperreflective foci (HF) and macular thickness on spectral domain ocular coherence tomography are associated with lipid levels in patients with Type 2 diabetes. METHODS: Two hundred and thirty-eight participants from four sites had fundus photographs and spectral domain ocular coherence tomography images graded for hard exudates and HF, respectively. Regression models were used to determine the association between serum lipid levels and 1) presence of HF and hard exudates and 2) central subfield macular thickness, central subfield macular volume, and total macular volume. RESULTS: All patients with hard exudates on fundus photographs had corresponding HF on spectral domain ocular coherence tomography, but 57% of patients with HF on optical coherence tomography did not have hard exudates detected in their fundus photographs. Presence of HF was associated with higher total cholesterol (odds ratio = 1.13, 95% confidence interval = 1.01-1.27, P = 0.03) and higher low-density lipoprotein levels (odds ratio = 1.17, 95% confidence interval = 1.02-1.35, P = 0.02) in models adjusting for other risk factors. The total macular volume was also associated with higher total cholesterol (P = 0.009) and triglyceride (P = 0.02) levels after adjusting for other risk factors. CONCLUSION: Higher total and low-density lipoprotein cholesterol were associated with presence of HF on spectral domain ocular coherence tomography. Total macular volume was associated with higher total cholesterol and triglyceride levels.

Influence of Glycosylated Hemoglobin on the Efficacy of Ranibizumab for Diabetic Macular Edema: A Post Hoc Analysis of the RIDE/RISE Trials.

PURPOSE: To investigate the influence of glycosylated hemoglobin (HbA1c) on treatment outcomes in patients with diabetic macular edema (DME) receiving intravitreal ranibizumab. DESIGN: Post hoc analysis of 2 identical phase III clinical trials assessing the efficacy and safety of intravitreal ranibizumab in DME over 36 months (RIDE: NCT00473382/RISE: NCT00473330). PARTICIPANTS: A total of 483 adults with vision loss from DME treated with ranibizumab were included in this analysis from RIDE/RISE. Participants received monthly intravitreal ranibizumab (0.3 or 0.5 mg). MAIN OUTCOME MEASURES: Differences in visual and anatomic outcomes, and diabetic retinopathy (DR) severity score, between subgroups of patients with baseline HbA1c ≤7% versus HbA1c >7% at 36 months. RESULTS: There were 195 patients in RIDE/RISE who were treated with ranibizumab with a baseline HbA1c ≤7% and 288 patients with a baseline HbA1c >7% included in this analysis. The mean improvement in visual acuity (VA) at 36 months was +13 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in patients with baseline HbA1c ≤7% compared with +11 ETDRS letters in the patients with a baseline HbA1c >7% (P = 0.17). After adjustment for baseline central foveal thickness (CFT) and duration of diabetes, the mean CFT reduction was -268 µm in patients with a baseline HbA1c ≤7% and -269 µm in patients with a baseline HbA1c >7% (P = 0.98; 95% confidence interval, -22.93 to 23.54). The proportion of patients with a ≥2-step improvement in DR severity score was 38% in patients with baseline HbA1c ≤7% compared with 41% in the patients with a baseline HbA1c >7% (P = 0.53). There was no correlation of baseline HbA1c with any visual or anatomic parameter. CONCLUSIONS: The improvement in VA, anatomic reduction of macular edema, and improvement in DR severity score with ranibizumab treatment seem to be independent of baseline HbA1c.

Serum neuron-specific enolase is elevated as a novel indicator of diabetic retinopathy including macular oedema.

AIM: Neuron-specific enolase as a potential biomarker of diabetic retinopathy, a neurovascular disease, had not been fully explored. We aimed to investigate the relationship between NSE and diabetic retinopathy. METHODS: Participants included Type 1 and Type 2 diabetes patients and healthy controls (n = 392). In this cross-sectional study, diabetic retinopathy status was assessed by fundus photographs. Serum neuron-specific enolase was measured using an electrochemiluminescence immunoassay. Co-variables for diabetic retinopathy and neuron-specific enolase were obtained from fasting blood samples and interviewer questionnaires. RESULTS: Neuron-specific enolase was slightly elevated in diabetic patients, in contrast to healthy participants, and obviously increased in diabetic patients with retinopathy compared with those without [8.3 (2.0) vs. 7.6 (1.5), P = 0.037 and 8.3 (2.0) vs. 9.5 (2.7), P = 0.004, respectively]. In addition, neuron-specific enolase levels increased with and were closely correlated to the stages of retinopathy without macular oedema [r = 0.60 (0.50-0.71), P = 0.002] and stages of macular oedema with comparable retinopathy [r = 0.58 (0.46-0.69), P = 0.006]. The association of neuron-specific enolase with diabetic retinopathy was independent [odds ration (OR): 1.31 (1.12-1.65), P = 0.017], after the diabetic state and other potential confounders affecting NSE levels were considered (e.g., HbA1c , duration, age, gender, renal status and medicines). The optimal cut-off point for serum neuron-specific enolase levels for differentiating between participants with diabetic retinopathy including macular oedema and those without was 9.3 µg/l, with a sensitivity of 67.5% and a specificity of 69.8%. CONCLUSIONS: Serum neuron-specific enolase is elevated in and indicative of diabetic retinopathy. Neuron-specific enolase may be a potential biomarker of diabetic retinopathy. Future prospective studies are warranted to clarify the relationship.

Serum cytokines as biomarkers for age-related macular degeneration.

PURPOSE: This study evaluates the potential of serum pro-inflammatory cytokines as AMD biomarkers. METHODS: Serum samples from 30 age-related macular degeneration (AMD) patients and 15 age-matched controls were examined for 16 inflammatory cytokines using multiplex ELISA. Patients were divided into three subgroups (improvement/no change/deterioration during anti-VEGF treatment) by OCT and funduscopy, and correlated to the cytokine levels. RESULTS: Serum concentrations of IL-1α, IL-1ß, IL-4, IL-5, IL-10, IL-13, and IL-17 were significantly higher in AMD patients than in controls. None of the co-variables expressed a significant effect on the tested cytokines. Only IL-1a and IL-17 showed a statistically significant difference between groups (improved, unchanged, deteriorated) as determined by one-way ANOVA. Patients with increased macular thickness during treatment showed significantly lower levels of IL-17 compared to improved cases and to unchanged cases (p = 0.004, 0.03 respectively, Dunnett's T3 post hoc multiple test). TNF-α was significantly higher in improved cases compared to deteriorated cases (p =0.03, Dunnett's T3 post hoc multiple test). IL-17 was a significant predictor for macular oedema using linear regression (ß = -0.888, p <0.05). CONCLUSION: Elevation of IL-1α, IL-1ß, IL-4, IL-5, IL-10, IL-13, and IL-17 in the serum of AMD patients supports the hypothesis of AMD as an inflammatory disease. Patients with high IL-17 and TNF-α serum levels were more likely to have a favourable course under VEGF therapy. These cytokines may be used as easy-to-obtain biomarkers.

Microaneurysm formation rate as a predictive marker for progression to clinically significant macular edema in nonproliferative diabetic retinopathy.

PURPOSE: To evaluate the predictive value of microaneurysm (MA) formation rate concerning the development of clinically significant macular edema (CSME) in patients with mild-to-moderate nonproliferative diabetic retinopathy as evaluated by an automated analysis of central field fundus 30° photographs. METHODS: Two hundred and eighty-seven eyes were included in the study. Photographs obtained at Day 0, at 6, and 12 months were analyzed using the RetmarkerDR software (Critical Health SA) in a masked manner, and the MA formation rate was documented. A threshold of a calculated MA formation rate of 2 or more was chosen to consider a patient "positive." The ability to predict CSME development was then calculated for a period of up to 5 years. HbA1c values, blood pressure, or duration of diabetes were also evaluated. RESULTS: The study population consisted of 89 male and 59 female patients with a mean age of 57.6 years, a mean HbA1c of 7.8, and a mean duration of diabetes of 12.3 years. Forty-seven of 287 eyes (16.4%) developed CSME during follow-up. An increased MA formation rate of >2 MA was clearly associated with development of CSME. Using the automated analysis and a threshold of 2 or more new MA, the authors were able to identify 70.2% of the eyes that developed CSME during follow-up ("true positive") and using a threshold of up to 2 new MA, 71.7% of the patients that did not develop CSME ("true negative"). No significant differences concerning baseline and 1-year HbA1c levels within patient eyes that developed CSME compared with patient eyes below or over the calculated threshold of 2 MA (P = 0.554 and P = 0.890, respectively) were seen. The positive and negative predictive value was calculated to be 33% versus 92.5%, sensitivity was 70%, and specificity was 72%. CONCLUSION: Using the RetmarkerDR software, the authors were able to identify patients with higher risk to develop CSME during follow-up using a threshold of 2 or more MA formation rate. Together with the high negative predictive value, the automated analysis may help to determine the individual risk of a patient to develop sight-threatening complications related to diabetic retinopathy and schedule individual screening intervals.

Vascular endothelial growth factor gene polymorphism prevalence in patients with diabetic macular oedema and its correlation with anti-vascular endothelial growth factor treatment outcomes.

BACKGROUND: To study the possible association between vascular endothelial growth factor gene polymorphism and diabetic macular oedema, and its correlation to the outcomes of anti-vascular endothelial growth factor treatment. DESIGN: Prospective study. PARTICIPANTS: 392 diabetic patients were included; 180 patients of them had no retinopathy, 212 patients had diabetic retinopathy. Diabetic retinopathy patients were classified into four groups as defined by the absence or presence of macular oedema or proliferative retinopathy. METHODS: In all subjects, polymerase chain reaction-restriction fragment length polymorphism was conducted to detect the vascular endothelial growth factor gene C-634G polymorphism. Serum levels of vascular endothelial growth factor were estimated. Changes of visual acuity and central macular thickness after bevacizumab treatment in diabetic macular oedema patients of different genotypes were monitored for 9-12 months. MAIN OUTCOME MEASURES: Vascular endothelial growth factor C-634G genotypes distribution in different groups; correlation between genotypes, and changes in visual acuity and central macular thickness after intravitreal bevacizumab treatment. RESULTS: CC genotype was significantly prevalent among diabetic macular oedema patients (P = 0.019). Significant higher serum levels of vascular endothelial growth factor were detected in diabetic retinopathy and diabetic macular oedema patients with CC genotype (P = 0.02, 0.016). After bevacizumab treatment, individuals with genotypes CG and GG have a decreased chance of positive treatment outcomes compared t with CC genotype (P < 0.001). CONCLUSIONS: Vascular endothelial growth factor C-634G polymorphism (CC genotype) is a genetic risk factor for diabetic macular oedema, and its presence provides significantly better visual outcome following bevacizumab treatment.